DISEASES OF THE RESPIRATORY ORGANS. 31 



(Pneumonia. 



An inflammation of the substance of the lungs, or pneumonia is charac- 

 terized by an exudation into the air cells, solidifying for a time that por- 

 tion of the lung affected. The first appreciable anatomical change in this 

 disease is an abnormal accumulation of blood, due to an active congestion 

 of the parts involved. This condition lasts but for a short time, and is 

 speedily followed by an exudation, a material which escapes from the 

 blood and coagulates within the air-cells. The cells are filled and dis- 

 tended with this exuded matter and cease to contain air. The lung is 

 solidified, presenting an appearance not unlike liver, and hence this con- 

 dition is called hepatization. 



If the progress of the disease be favorable, the exudation is removed 

 mainly or exclusively by absorption, and the recovery of the affected 

 part is complete. If the disease progresses unfavorably, absorption of the 

 product within the air cells does not take place, the substance of the lung 

 softens and breaks down, a condition called purulent infiltration. 



The constitutional symptoms then become more marked, the distress 

 more apparent. The expression grows even more piteous and haggard, 

 the eyes more sunken. The nostrils dilate, the cough loose, becomes per- 

 sistent and distressing, and the mouth and lips are covered with a thick 

 slime. The breath which has a sweet, sickish odor, comes quick and short. 

 Approaching suffocation is obvious. The sitting position so long main- 

 tained is still persevered in, until the limbs become dropsical, the skin 

 cold and clammy, the pulse faint and flickering, finally death ends all. 



Causation.— While exposure to cold, is an evident cause of pneumonia 

 in many cases, it is probably but an exciting influence co-operating with 

 an existing morbid condition or predisposition, which we are unable to 

 comprehend. The disease is in many cases developed spontaneously, no 

 obvious cause apparent. 



Symptoms. — The, invasion of the disease is often abrupt. In a large 

 proportion of cases pneumonia is ushered in with a chill, as shown by 

 shiverings. Speedily following the chill pain is manifest, in some cases 

 severe, in others very slight. Cough usually appears soon after the attack 

 commences. It may be prominent, and is sometimes wanting. The matter 

 coughed up is at first scanty and thick. In a certain proportion of cases 

 it soon assumes a character distinctive of the disease termed rusty, from 

 its reddish tint like iron rust. 



Fever follows immediately the invasion of the disease. The pulse runs 

 high, loss of appetite occurs, great thirst is experienced, and prostration 

 manifested. The nose becomes hot and dry, the eyes reddened. The res- 

 pirations increase in frequency, as the disease progresses, until a sense 



